What pressures do you run in your tyres?

[maddog]

What pressures do you run on and off road in your various types of tyres?

Thought this might make an interesting discussion thread.

My old 35x12.5 radial Claws were run at about 28PSI on the road, and 7PSI front and 9PSI rear off road. This was with internal bead locks on 15x8" steel wheels.

Prior to that I had 32x11.5 Goodyear MTRs. I ran them at about 14-15PSI off road and about 35 on road. No bead locks.

I've got a set of 37x12.5 MTRs for on road and light 4WDing now, and a set of 38.5x14.5 TSL/SX for competition and hard offroad. No idea what pressure I'll be running these on and off road yet, but the TSLs are fitted to 15x10 mechanical bead locks and the MTRs will be fitted to 15x10 regular steel wheels when I get hold of a set.

[H.G.]

33 claws..
on road 28psi
off road 18psi
no bead locks

[zzzz]

36" simexs on beadlocks
22-24 psi onroad
4-6 psi offroad

34" simex on steelies
24-28 onroad
10-12 psi offroad

I would just play around with your tyres and find out what works.
It all comes down to how flexible the carcass is and at what pressure compared to the weight of your jeep that they really start to flex.

On road you can draw a chalk line across the tread, air them up to a certain pressure then go for a drive. Stop and have a look at where the chalk has worn off. then adjust the pressure to suit.

Off road a decent way to work out the correct pressure is to grab a piece of 2x4 or something solid that is at least a few inches tall and wide, and drive the tyre onto it. Then see what the tyre looks like. Is it on top of the object or is it wrapping around it? Increase or decrease as required

cheers

z

[stu]

33 claws on 15 X 8 (muddies)
on road 30psi
off road 16 - 18 psi (im never that exact)
no bead locks

33 maxxis on 15 x 8 (roadies)
on road 35psi
off road 22psi

[Jimmyb]

used to ru nthe 35" Bias claws @ 4psi off road with locks.

I have noticed though watching a lot fo thw we rock footage that a lot of those guys arent really airing down that much, their rubber doesnt seem to be bagging....... am i missing something? and they wonder why they jump and bounce everywhere.

[wiz]

s'pose you may already know Dawg , but just for the hell of it :

35 mtrs
8in alloy - no beadlocks
Onroad : 28 -32 psi
Offroad : 7 - 9 psi ( although usually around 8 )

[maddog]

Originally Posted by JimmyB

used to ru nthe 35" Bias claws @ 4psi off road with locks.

I have noticed though watching a lot fo thw we rock footage that a lot of those guys arent really airing down that much, their rubber doesnt seem to be bagging....... am i missing something? and they wonder why they jump and bounce everywhere.

That's one of the reasons I created the thread. I was watching some WE Rock footage on the weekend and noticed the same thing.

What I assumed is that a lot of guys who want to drive in comps like that watch American rock crawling DVDs, and those guys don't seem to air down much at all.

I guess their logic is that they want less sidewall, and less sidewall flex to cope with off camber situations. My opinion though is that I'm willing to sacrifice a bit of sidewall stiffness and *possible* off camber stability for a tonne more grip over rocks. If you set your rig up right, it can be tall and still stable off camber so you don't neccessarily have to worry about how soft your tyres are going to be and if that will be the difference between you rolling or not.